Field of the Invention
The present invention relates to a process for precipitation hardening of a metal alloy that has been coated with tantalum.
Introduction
Metal alloys can be protected from corrosive attack by applying a coating of tantalum to the metal. Tantaline Inc. offers a service for vapor depositing tantalum onto metallic alloy substrates as a protective coating. The process requires heating a metallic alloy substrate in an oven to temperatures of 700-900 degrees Celsius (° C.) at which time tantalum metal precursor is vaporized and deposited onto the substrate. Unfortunately, heating the substrate metal alloy to such a high temperature can partially or completely anneal the substrate metal alloy thereby causing the substrate metal alloy to lose some of its desired physical properties such as hardness, tensile modulus and compressive modulus. Such is the case when the metal alloy substrate is a precipitation hardened (PH) metal alloy where that tantalum coating process results in loss of physical properties characteristic of being precipitation hardened.
It is desirable to discover how to obtain a tantalum coated PH metal alloy that benefits from both the durable tantalum coating and the precipitation hardened properties of the metal substrate.